Semiconductor light-emiting device and method

ABSTRACT

A semiconductor light-emitting device can include a submount on which a semiconductor light-emitting element is mounted. The device can have a high light utilization efficiency with high reliability and can achieve a reduction in manufacturing cost as well as a decrease in size. The submount can have a reverse trapezoidal cross section having an upper surface that is larger than a bottom surface of the semiconductor light-emitting element. An adhesive can be used to fix the submount to the base board such that, when the submount is observed from above the semiconductor light-emitting element, the adhesive is not seen from above. In this state, the semiconductor light-emitting element can be connected to the base board via a bonding wire.

This application claims the priority benefit under 35 U.S.C. §120 and isa Divisional application of U.S. patent application Ser. No. 11/536,170filed on Sep. 28, 2006, which is hereby incorporated in its entirety byreference. This application also claims the priority benefit under 35U.S.C. §119 of Japanese Patent Application No. 2005-284807 filed on Sep.29, 2005, which is hereby incorporated in its entirety by reference.

BACKGROUND

1. Field

The presently disclosed subject matter relates to semiconductorlight-emitting devices, and in particular, to a semiconductorlight-emitting device having a configuration in which a semiconductorlight-emitting element is mounted on a submount.

2. Description of the Related Art

FIG. 1 shows the configuration of a conventional semiconductorlight-emitting device. The conventional semiconductor light-emittingdevice is configured to include: a submount 51 having a recess 50; alead frame 52 on which the submount 51 is fixed; a semiconductor laserelement 54 placed on the bottom surface 53 of the recess 50; bondingpads 56 connected to a wiring pattern extending from the bottom surface53 of the recess 50 via an inner peripheral surface 55 (the wiringpattern is not shown in the drawing, but is configured for electricallyconnecting the electrode of the semiconductor laser element 54 to thebonding pads 56), the bonding pads 56 being provided on the upper faceof the side walls of the submount 51; bonding wires 57 for electricallyconnecting the bonding pads 56 to the lead frame 52; an encapsulatingmaterial 58 located in the recess 50 of the submount 51 to seal thesemiconductor laser element 54; and a mold resin portion 59 forresin-sealing the submount 51 including the encapsulating material 58,the bonding wires 57, and the lead frame 52. (See, for example, theconventional art reference to Hideo Tamura et al.—Japanese PatentLaid-Open Publication No. 2001-68741.)

In the above-described semiconductor light-emitting device, the submount51 is fixed on the lead frame 52 via an adhesive. In this instance, theadhesive may spread beyond the outer periphery 60 of the submount 51.For example, when the submount 51 having the recess is fixed on the leadframe 52 by means of an adhesive 70, as shown in FIG. 2, the adhesive 70is in contact with the outer bottom surface 71 and the outer periphery60 of the submount 51, and the lead frame 52. At the same time, theadhesive 70 may spread beyond the outer periphery 60 of the submount 51over the lead frame 52 because it is pressed by the outer bottom surface71 of the submount 51.

Under this situation, one end of the bonding wire 57 can be connected tothe bonding pad 56 provided on the upper face of the side wall of thesubmount 51, but the other end thereof must be connected to the leadframe 52 at a position which is away from the outer periphery 60 of thesubmount 51 and is not covered with the adhesive 70 to avoid theadhesive 70 spreading over the lead frame 52.

In this case various problems arise, including the requirement that thebonding wire 57 be long to avoid the adhesive 70. This may increase thematerial cost, thereby also increasing the overall manufacturing cost.Depending on the amount of adhesive 70 that spreads outward beyond theouter periphery 60 of the submount 51 and the connecting position of thebonding wire 57, the semiconductor light-emitting device may inevitablybecome large in size. Furthermore, the wiring shape of the bonding wire57 (loop shape) may change as shown by the dotted circle in FIG. 2because the wiring length of the bonding wire 57 increases and thebonding wire 57 tends to receive the injection pressure of the moldresin 59 for sealing the bonding wire 57. In this case, the bonding wire57 may be deformed to weaken the mechanical strength thereof against theresin stress. In other words, the resin stress received by the bondingwires 57 may vary depending on the difference between the thermalexpansion coefficients of the bonding wire 57 and the mold resin 59sealing the bonding wire 57. This may occur due to the high temperatureenvironment during the mounting of the semiconductor light-emittingdevice on a mother board, or due to the temperature variationenvironment present due to the repeated turning on/off of thesemiconductor light-emitting device mounted on the mother board. As aresult of this, the bonding wire 57 may break or come off at itsconnecting portion or other like problems may occur, causing electricalfailure of the connection.

In order to reduce the problems described above, it is conceivable tostrengthen the resistance against the injection pressure of the moldresin by adopting a bonding wire with a larger diameter. However, thisinvolves an increase in cost. Alternatively, it is conceivable that theamount of adhesive used for fixing the submount onto the lead frame canbe decreased to narrow the range of spreading of the adhesive beyond thesubmount periphery. In this instance, the bonding wire can be shortenedmore than the previous case because the range of spreading of theadhesive may be narrowed and the bonding wire can be bonded nearer, inorder to strengthen the resistance against the injection pressure of themold resin. However, this may weaken the bonding strength of thesubmount to the lead frame.

Another conventional semiconductor light-emitting device is shown inFIG. 3 in which a semiconductor light-emitting element 80 is fixed tothe plate-shaped submount 51 via an adhesive 70. In this instance, as inthe previous conventional example, the adhesive 70 may spread beyond theside face 72 of the submount 51 outside the bottom surface 82 of thesubmount 51.

When power is supplied to the semiconductor light-emitting element 80,the light emitted from a side wall 81 side of the element 80 may beabsorbed by the adhesive 70 as shown by the dotted small circle in FIG.3. Therefore, the light utilization efficiency of the semiconductorlight-emitting element 80 may deteriorate, thereby making thesemiconductor light-emitting device emit light with a lower intensity.

SUMMARY

In view of the foregoing and other problems and characteristics ofconventional devices, an aspect of the disclosed subject matter includesproviding a semiconductor light-emitting device having a structure inwhich a semiconductor light-emitting element is mounted on a submountwith high light utilization efficiency and reliability. The disclosedsubject matter includes a small-sized semiconductor light-emittingdevice with possibly lower cost, greater manufacturability, and otherpossible characteristics and features.

One of the aspects of the presently disclosed subject matter is asemiconductor light-emitting device that can include: a submount havingat least a pair of surfaces substantially parallel to each other; asemiconductor light-emitting element placed on one of the pair of thesurfaces of the submount; a base board on which the submount is fixedwith the other surface via a fixing member; and a seal resin for sealingat least the semiconductor light-emitting element and the submount. Inthe semiconductor light-emitting device as configured above, the othersurface of the submount fixed on the base board can have a smaller areathan a maximum cross section of the submount cut along a plane parallelto the pair of surfaces of the submount.

In the semiconductor light-emitting device, the fixing member may notexist beyond the submount when viewed from a direction above thesemiconductor light-emitting element mounted. The submount may have areversed trapezoidal cross section cut along a direction perpendicularto the base board.

In the semiconductor light-emitting device, the submount may have afirst surface larger in area than a bottom surface of the placedsemiconductor light-emitting element. Alternatively, the submount mayhave a first surface that has the same area as that of a bottom surfaceof the placed semiconductor light-emitting element.

The submount may have a stepped portion, and side walls of the submountother than the stepped portion may be perpendicular to the base board.In this case, the submount may have a first surface larger in area thana bottom surface of the placed semiconductor light-emitting element.Alternatively, the submount may have a first surface having the samearea as that of a bottom surface of the placed semiconductorlight-emitting element.

In the semiconductor light-emitting device, the submount may have awedge-shaped cross section when cut along a direction perpendicular tothe base board. Side walls of the submount may be inclined inward from amiddle portion to the upper side and to the lower side.

The submount may have a wedge-shaped cross section when cut along adirection perpendicular to the base board, and a part of a side wall ofthe submount may be inclined inward and the other part of the side wallmay be perpendicular to the base board.

Another aspect of the presently disclosed subject matter includes asemiconductor light-emitting device that can include: a submount havinga recess and a lower surface, and an inner bottom surface located withinthe recess; a semiconductor light-emitting element placed on the innersurface within the recess of the submount; a base board on which thelower surface of the submount is fixed via a fixing member; a seal resinfor sealing at least the semiconductor light-emitting element and thesubmount. In the above semiconductor light-emitting device, the lowersurface of the submount that is fixed on the base board can have asmaller area than a maximum cross section of the submount cut along aplane parallel to the lower surface of the submount.

In the above semiconductor light-emitting device, the fixing member maynot exist beyond a periphery of the submount when viewed from adirection above the semiconductor light-emitting element mounted.

An outer peripheral surface of the submount may include: the lowersurface; a middle surface extending from the lower surface upward, themiddle surface inclined outward; and a perpendicular surface to thelower face, the perpendicular surface extending from an upper end of thesubmount to the middle surface. The outer peripheral surface may have astepped portion and a side wall of the submount from the stepped portionto the lower surface may be perpendicular to the base board. The recessmay have a mortar shape.

As described above, the semiconductor light-emitting device can employ afixing member which does not exist beyond a periphery of the submountarea when viewed from a direction above the mounted semiconductorlight-emitting element, due to the specific shape and features of thesubmount structure.

As a result of this, the bonding wire can be bonded to a position nearerto the submount than the case of typical conventional devices. Thus, thelength of the bonding wire can be shortened. This can reduce bothmaterial costs as well as manufacturing costs. Furthermore, a sizereduction of the semiconductor light-emitting device can be achieved.Also, the shortened bonding wire can have a stronger resistance againstthe injection pressure of the seal resin for sealing the bonding wirewithout varying the wiring shape (loop shape) of the bonding wire. Thiscan avoid electrical failure due to the injection pressure, and canimprove quality and reliability.

Furthermore, the light emitted from the side wall of the semiconductorlight-emitting element can be reflected by the upper surface of thesubmount to be directed toward the light emitting surface of thesemiconductor light-emitting device, thereby improving the lightutilization efficiency of the light-emitting element. This can result ina high intensity semiconductor light-emitting device.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics, features, and advantages of thedisclosed subject matter will become clear from the followingdescription with reference to the accompanying drawings, wherein:

FIG. 1 is a cross-sectional view showing a conventional semiconductorlight-emitting device;

FIG. 2 is a cross-sectional view showing another conventionalsemiconductor light-emitting device;

FIG. 3 is a cross-sectional view showing still another conventionalsemiconductor light-emitting device;

FIG. 4 is a cross-sectional view showing an embodiment of a submountwith a semiconductor light-emitting element mounted thereon, both ofwhich are components of an embodiment of a semiconductor light-emittingdevice made in accordance with principles of the presently disclosedsubject matter;

FIG. 5 is a cross-sectional view showing another embodiment of asubmount structure for a semiconductor light-emitting device made inaccordance with principles of the disclosed subject matter;

FIG. 6 is a cross-sectional view showing still another embodiment of asubmount structure for a semiconductor light-emitting device made inaccordance with principles of the disclosed subject matter;

FIG. 7 is a cross-sectional view showing still another embodiment of asubmount structure for a semiconductor light-emitting device made inaccordance with principles of the disclosed subject matter;

FIG. 8 is a cross-sectional view showing still another embodiment of asubmount structure for a semiconductor light-emitting device made inaccordance with principles of the disclosed subject matter;

FIG. 9 is a cross-sectional view showing still another embodiment of asubmount structure for a semiconductor light-emitting device made inaccordance with principles of the disclosed subject matter;

FIG. 10 is a cross-sectional view showing still another embodiment of asubmount structure for a semiconductor light-emitting device made inaccordance with principles of the disclosed subject matter;

FIG. 11 is a cross-sectional view showing still another embodiment of asubmount structure for a semiconductor light-emitting device made inaccordance with principles of the disclosed subject matter;

FIG. 12 is a cross-sectional view showing still another embodiment of asubmount structure for a semiconductor light-emitting device made inaccordance with principles of the disclosed subject matter;

FIG. 13 is a cross-sectional view showing still another embodiment of asubmount structure for a semiconductor light-emitting device made inaccordance with principles of the disclosed subject matter;

FIG. 14 is a cross-sectional view showing an embodiment of a mountingstate for a submount with a semiconductor light-emitting element inaccordance with principles of the disclosed subject matter;

FIG. 15 is a cross-sectional view showing another embodiment of amounting state for another submount with a semiconductor light-emittingelement in accordance with principles of the disclosed subject matter;and

FIGS. 16A to 16E show process steps for fabricating an embodiment of asemiconductor light-emitting device made in accordance with principlesof the disclosed subject matter.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Hereinafter, exemplary embodiments of the disclosed subject matter willbe described in detail with reference to FIGS. 4 to 16E (the samereference numerals refer to the same or similar parts). The exemplaryembodiments described hereinafter are specific examples of the disclosedsubject matter, and thus various technical features are applied thereto.However, the scope of the presently disclosed subject matter is notlimited to the exemplary embodiments.

FIGS. 4 to 13 are each a cross-sectional view showing differentexemplary embodiments of a submount for use in semiconductorlight-emitting devices made in accordance with principles of thepresently disclosed subject matter. The submounts shown in FIGS. 4 to 9each have a substantial plate block shape having a pair of substantiallyparallel surfaces with a different side surface (also cross section).The submounts shown in FIGS. 10 to 13 each have a recess and a differentouter periphery with a generally U-shaped cross-section.

A semiconductor light-emitting element can be placed on each of thesubmounts shown in FIGS. 4 to 13. Of these, in FIGS. 4 to 9 asemiconductor light-emitting element is mounted on a submount having asubstantially plate-shaped block. In FIGS. 10 to 13, a semiconductorlight-emitting element is mounted on a bottom surface within a recess ofa submount having a generally U-shaped cross section.

A description will be given of the respective shapes of the submountsshown in FIGS. 4 to 13.

The submount 1 shown in FIG. 4 has an upper surface 3 and a lowersurface 5. The upper surface 3 can be used for mounting a semiconductorlight-emitting element 2 thereon and can have a larger area than thearea of the bottom surface 4 of the semiconductor light-emitting element2 and the area of the lower surface 5 of the submount 1. The uppersurface 3 can be substantially parallel to the lower surface 5.Therefore, the side surface 6 of the submount 1 is inclined inward fromthe upper surface 3 side to the lower surface 5 side. The submount 1 canhave a reversed trapezoidal cross section when cut along the directionperpendicular to the base board. It may be desirable in certainapplications that an angle θ formed by the upper surface 3 and the sidesurface 6 of the submount 1 be smaller than 90 degree (θ<90°). The angleθ may also be larger than 45° and smaller than 60° (45°<θ<60°) in viewof bonding stability of the lower surface 5 of the submount 1.

The submount 1 shown in FIG. 5 has a similar figure in cross section tothat of the submount 1 shown in FIG. 4. The upper surface 3 can be usedfor mounting the semiconductor light-emitting element 2 and can havesubstantially the same area as that of the bottom surface 4 of thesemiconductor light-emitting element 2.

The submount 1 shown in FIG. 6 has a two-level structure including anupper part 7 and a lower part 8. The upper part 7 can include an uppersurface 3 on which a semiconductor light-emitting element 2 is mounted.The lower part 8 has a lower surface 5. The upper surface 3 can have alarger area than that of the bottom surface 4 of the semiconductorlight-emitting element 2. A step portion can be provided between theupper part 7 and the lower part 8 and can be larger than the lowersurface 5. Side surfaces 6 of the upper part 7 and the lower part 8 canbe made substantially perpendicular to the upper surface 3 and the lowersurface 5.

The submount 1 shown in FIG. 7 has a similar figure in cross section tothat of the submount 1 shown in FIG. 6. The upper surface 3 thereof formounting the semiconductor light-emitting element 2 can havesubstantially the same area as that of the bottom surface 4 of thesemiconductor light-emitting element 2.

The submount 1 shown in FIG. 8 has a two-level structure including anupper part 7 and a lower part 8. The upper part 7 has an upper surface 3on which a semiconductor light-emitting element 2 can be mounted. Thelower part 8 has a lower surface 5. The side surface 6 a of the upperpart 7 can be inclined outward from the upper surface 3 side to thelower part side. On the other hand, the side surface 6 b of the lowerpart 8 can be inclined outward from the lower surface 5 side to theupper part side. Namely, the entire cross section of the submount 1 canhave a wedge shape. The side surfaces 6 a and 6 b can contact with eachother at the boarder of the upper and lower portions 7 and 8. In thisexemplary embodiment, the upper surface 3 of the submount 1 has an areathat is substantially the same as that of the bottom surface 4 of thesemiconductor light-emitting element 2 to be mounted thereon.

The submount 1 shown in FIG. 9 has a two-level structure including anupper part 7 and a lower part 8. The upper part 7 has an upper surface 3on which a semiconductor light-emitting element 2 can be mounted. Thelower part 8 has a lower surface 5. The side surface 6 a of the upperportion 7 can be inclined outward from the upper surface 3 side to thelower part side, thereby providing a wedge-shaped cross section for theupper portion. On the other hand, the side surface 6 b of the lower part8 can be substantially perpendicular to the lower surface 5. The uppersurface 3 can have an area that is substantially the same as that of thebottom surface 4 of the semiconductor light-emitting element 2. Theupper part 7 can include a larger area at the boarder area between theupper and lower parts 7 and 8 than lower surface 5 of the lower part 8.

The submount 1 shown in FIG. 10 has a recess 11, which has asubstantially flat inner bottom surface 9 and an inner peripheralsurface 10 substantially perpendicular to the inner bottom surface 9. Onthe inner bottom surface 9, a semiconductor light-emitting element 2 canbe placed. In addition, the submount 1 can have a lower surface 5 thatis substantially parallel to the inner bottom surface 9 of the recess11. The submount 1 can also include an outer peripheral surface 13 thathas a surface substantially perpendicular to the lower surface 5 andwhich extends from the upper edge 12 of the submount 1 toward the lowerside. The outer peripheral surface 13 can also include an inclinedsurface that extends between the lower surface 5 and the outerperpendicular surface and is outwardly inclined from the lower surface 5toward the outer perpendicular surface.

The submount 1 shown in FIG. 11 is approximately the same shape as thatof the submount 1 shown in FIG. 10, except for the surface connectingthe outer perpendicular surface and the lower surface 5. The connectingsurface area includes a perpendicular surface and a parallel surface asshown in the drawing.

The submount 1 shown in FIG. 12 has substantially the same shape as thatof the submount 1 shown in FIG. 10, except for the inner peripheralsurface 10 having a mortar shape (inclined inwardly from the upperedge).

The submount 1 shown in FIG. 13 is approximately the same shape as thatof the submount 1 shown in FIG. 12, except for the surface connectingthe outer peripheral perpendicular surface and the lower surface 5. Theconnecting surface area includes a perpendicular surface and a parallelsurface as shown in the drawing.

It should be appreciated that the material of the submount can beconfigured to meet the performance requirements, including highprocessability, high durability, and/or good heat dissipation propertiesfor use when turning on the mounted element that is to be lit. Examplesof the material include, but are not limited to, insulating materialssuch as glass epoxy resins and ceramics, metal materials such as Au, Cu,Al, and alloys of these metal materials, semiconductor materials such asSi and Si derivatives, etc. Taking heat dissipation property intoconsideration, metal materials can be used in certain applications toprovide good heat dissipation. In order to improve the heat dissipationproperty, the thickness of the submount may be reduced.

The submount 1 on which the semiconductor light-emitting element 2 ismounted can be connected onto a base board, thereby completing or takinga step to complete the fabrication of the semiconductor light-emittingdevice. Hereinafter, the connecting structure for fixing the submount tothe base board will be described with reference to FIGS. 14 and 15, inwhich two types of the submounts 1 are exemplified among those shown inFIGS. 4 to 13.

FIG. 14 shows a state wherein the submount 1 shown in FIG. 4 isconnected to the base board 15 via an adhesive 14 (e.g., Ag paint). Theadhesive 14 can be in contact with the lower surface 5 and the sidesurface 6 of the submount 1, and the surface 16 of the base board 15.The adhesive 14 that is located beyond the side face 6 of the submount 1spreads over the surface 16 of the base board 15. In this instance, theupper surface 3 of the submount 1 to which the semiconductorlight-emitting element 2 is mounted can be larger than the bottomsurface 4 of the semiconductor light-emitting element 2 and the lowersurface 5 of the submount 1. Therefore, the side surface 6 can beinwardly inclined from the upper surface 3 side toward the lower surface5. As a result of this, the submount 1 can have a reverse trapezoidshape in cross section.

In this case, the adhesive 14 may spread over the surface 16 of the baseboard 15 from the side surface 6 of the submount 1 outward. The adhesive14 may also be interposed between the inclined side surface 6 of thesubmount 1 and the surface 16 of the base board 15. In addition to theabove-described configuration, the end 17 of the adhesive 14 thatspreads outward from the side surface 6 of the submount 1 over thesurface 16 of the base board 15 can terminate within the areacorresponding to the edge 18 of the upper surface 3 of the submount 1(the area corresponding to the upper surface 3 of the submount 1).

When the connecting state of the submount 1 onto the base board 15 isobserved from above the semiconductor light-emitting element 2, theadhesive 14 is not seen from above because the adhesive 14 is hidden bythe submount 1.

In order to terminate the flow of the adhesive 14 within the edge 18 ofthe upper surface 3 of the submount 1, the distance L as shown in FIG.14 can be set within a range of approximately 75 to 215 μm wherein thedistance L is defined as a distance between the edge 19 of the lowersurface 5 and the edge 18 of the upper surface 3 when projected onto asame plane.

In accordance with the above-described configuration, the bonding wire20 can be bonded to a position nearer to the submount 1. This canshorten the wiring length of the bonding wire 20. Therefore, thematerial cost as well as the manufacturing cost can be reduced ormaintained. Furthermore, a reduction in size of the semiconductorlight-emitting device may be achieved. Also, the shortened bonding wire20 can have a stronger resistance against the injection pressure of theseal resin for sealing the bonding wire 20 without varying the wiringshape (loop shape) of the bonding wire 20. This avoids possibleelectrical failure due to the injection pressure and ensures the highquality and reliability of the lighting device.

Furthermore, the light emitted from the side surface 21 of thesemiconductor light-emitting element 2 can be reflected by the uppersurface 3 of the submount 1 such that it is directed toward a lightemitting surface of the semiconductor light-emitting device, therebyimproving the light utilization efficiency of the light-emitting element2. The above described configuration can achieve a high intensitysemiconductor light-emitting device.

FIG. 15 shows a state wherein the submount 1 shown in FIG. 6 isconnected to the base board 15 via a soldering material 22. In thiscase, the soldering material 22 rises along the side surface 6 of thesubmount 1 at the lower part 8, and also spreads over the surface 16 ofthe base board 15, to ensure the bonding of the submount 1 onto the baseboard 15. In order to facilitate rising of the soldering material 22,the side surface 6 of the lower part 8 of the submount 1 can besubstantially perpendicular to the lower surface 5 of the submount 1 (orsubstantially perpendicular to the surface 16 of the base board 15).

In this case, the end 23 of the soldering material 22 that spreadsoutward from the side surface 6 of the submount 1 over the surface 16 ofthe base board 15 can terminate within the area corresponding to theedge 18 of the upper surface 3 of the submount 1.

When the connecting state of the submount 1 onto the base board 15 isobserved from above the semiconductor light-emitting element 2, thesoldering material 22 may not be seen from above because the solderingmaterial 22 is hidden by the submount 1.

Therefore, as in the exemplary embodiment shown in FIG. 14, the bondingwire 20 can be bonded to a position nearer to the submount 1. This canshorten the wiring length of the bonding wire 20. Therefore, thematerial cost as well as the manufacturing cost can be maintained orreduced. Furthermore, a reduction in size of the semiconductorlight-emitting device can be achieved. Also, the shortened bonding wire20 can have a stronger resistance against the injection pressure of theseal resin for sealing the bonding wire 20 without varying the wiringshape (loop shape) of the bonding wire 20. Thus, electrical failure dueto the injection pressure can be avoided, and high quality andreliability in the lighting device can be achieved.

It should be appreciated that a metal film with a high reflectivity canbe formed on the upper surface of the submount where the semiconductorlight-emitting element is mounted and bonded. The metal film can beformed by CVD technique, sputtering technique, or other techniques. Thisconfiguration can improve the light utilization efficiency of thesemiconductor light-emitting element, thereby increasing the intensityof light emitted from the semiconductor light-emitting device.Furthermore, meshed grooves may be formed on the upper surface of thesubmount in order to increase the bonding strength between the submountand the semiconductor light-emitting element. A circuit pattern that isto be connected to electrodes of the semiconductor light-emittingelement may be formed on the upper surface of the submount in order tosupply power to the semiconductor light-emitting element from anexterior power source.

Examples of the material for fixing a submount to a base board include,but are not limited to, Ag paste, silicone resin-based adhesives, epoxyresin-based adhesives, soldering materials, and the like. If siliconeresin-based or epoxy resin-based adhesives are employed, fillers may becontained therein in order to increase the heat conductivity. Examplesof the base board used herein include, but are not limited to,insulating materials with wiring such as glass epoxy substrates, ceramicsubstrates such as aluminum nitride substrates, metal substrates withwiring (metal including Al, Cu, and the like), etc.

A method for manufacturing a semiconductor light-emitting deviceemploying a submount in accordance with the disclosed subject matterwill be described below, with reference to FIGS. 16A to 16E.

As shown in FIG. 16A, a plurality of semiconductor light-emittingelements 2 are mounted onto an unprocessed submount material at regularintervals.

As shown in FIG. 16B, the submount material can be cut into submounts 1each having the semiconductor light-emitting element 2 mounted thereonsuch that the side surface from the upper surface 3 side to the lowersurface 5 side is inwardly inclined.

As shown in FIG. 16C, the separated submount 1 with the semiconductorlight-emitting element 2 can be fixed onto a base board 15 via anadhesive 14.

As shown in FIG. 16D, bonding wires 20 can be used to electricallyconnect the semiconductor light-emitting element 2 and a circuit patternassociated with the base board 15 (the circuit pattern thereon is notshown).

As shown in FIG. 16E, the semiconductor light-emitting element 2, thesubmount 1, the bonding wires 20, and the base board 15 can be sealedwith a sealing resin 24 (e.g., a transparent resin with or without awavelength conversion material) to complete the semiconductorlight-emitting device.

While there has been described what are at present considered to beexemplary embodiments of the invention, it will be understood thatvarious modifications may be made thereto, and it is intended that theappended claims cover such modifications as fall within the true spiritand scope of the invention. All conventional art references describedabove are herein incorporated in their entirety by reference.

1. A semiconductor light-emitting device comprising: a submount having afirst surface, a second surface that is substantially parallel to thefirst surface, and a third surface connecting the first surface and thesecond surface; a semiconductor light-emitting element located adjacentthe first surface of the submount; a base board on which the secondsurface of the submount is fixed via a fixing member; and a transparentseal resin configured to seal at least the semiconductor light-emittingelement and the submount so that the transparent seal resin also coversat least a part of the third surface and a part of the base board,wherein the second surface of the submount that is fixed on the baseboard has a smaller area than a maximum cross section area of thesubmount cut along a plane substantially parallel to both the firstsurface and the second surface of the submount.
 2. The semiconductorlight-emitting device according to claim 1, wherein the fixing memberdoes not exist beyond the submount when viewed from a direction abovethe semiconductor light-emitting element when mounted to the submount.3. The semiconductor light-emitting device according to claim 1, whereinthe submount has a reverse trapezoidal cross section when cut along adirection substantially perpendicular to the base board; and the firstsurface of the submount has an area that is substantially the same as anarea of a bottom surface of the semiconductor light-emitting elementthat is connected to the first surface of the submount.
 4. Thesemiconductor light-emitting device according to claim 1, wherein thesubmount has a stepped portion, and a part of the third surface of thesubmount located outside of the stepped portion is substantiallyperpendicular to the base board.
 5. The semiconductor light-emittingdevice according to claim 4, wherein the first surface of the submounthas an area that is larger than an area of a bottom surface of thesemiconductor light-emitting element that is connected to the firstsurface of the submount.
 6. The semiconductor light-emitting deviceaccording to claim 4, wherein the first surface of the submount has anarea that is substantially the same as an area of a bottom surface ofthe semiconductor light-emitting element that is connected to the firstsurface of the submount.
 7. The semiconductor light-emitting deviceaccording to claim 1, wherein the submount has a wedge-shaped crosssection when cut along a direction substantially perpendicular to thebase board, and the third surface of the submount is inwardly inclinedfrom a middle portion towards both the first surface and the secondsurface of the submount.
 8. The semiconductor light-emitting deviceaccording to claim 1, wherein the submount has a wedge-shaped crosssection when cut along a direction substantially perpendicular to thebase board, and a part of the third surface of the submount is inwardlyinclined and another part of the third surface is substantiallyperpendicular to the base board.
 9. The semiconductor light-emittingdevice according to claim 1, wherein: the submount includes a recess inthe first surface, the recess including an inner bottom surface; thesemiconductor light-emitting element is located adjacent the innerbottom surface within the recess of the submount.
 10. The semiconductorlight-emitting device according to claim 9, wherein the third surfacehas: a middle surface extending from the second surface upward, themiddle surface inclined outward; and a perpendicular surface that issubstantially perpendicular to the second surface, the perpendicularsurface extending from an upper end of the submount to the middlesurface.
 11. The semiconductor light-emitting device according to claim9, wherein the third surface has a stepped portion, and a part of thethird surface located between the stepped portion and the second surfaceis substantially perpendicular to the base board.
 12. The semiconductorlight-emitting device according to claim 10, wherein the recess has amortar shape.
 13. The semiconductor light-emitting device according toclaim 11, wherein the recess has a mortar shape.
 14. The semiconductorlight-emitting device according to claim 1, wherein the fixing member isan adhesive.
 15. The semiconductor light-emitting device according toclaim 1, wherein the semiconductor light-emitting element is connectedto the base board via a bonding wire.
 16. A method of manufacturing thesemiconductor light-emitting device according to claim 1, comprising:attaching the submount to the base board with the fixing member; andpreventing the fixing member from extending beyond an outer periphery ofthe submount when the semiconductor light-emitting device is viewed froma light emitting direction of the semiconductor light emitting device.